Class Conjugatophyceae Engl. (1892) see Class Zygnematophyceae Round ex Guiry (2013) Order Zygnematales - filamentous conjugates and saccoderm desmids Family Zygnemataceae (Meneghini) Kützing (1843) Genus Zygnema C.Agardh (1817), nom. cons. Zygnema stellinum (O.F.Müll.) C.Agardh